Telephone receiver



Nov. 1, 1927.

H. KOCH ET AL. TELEPHONEl RECEIVER Filed NOV. 14, 1925 ATTORNEYS Patented Nov. 1, 1927.

' UNITEDLSTATES L 1,647,182 PATENT OFFICE.

HENRY KOCH, OF JAMAICA, FRIEDRICH H. N. 17OHLERS,I OF HEMPSTEAD, YORK, ASSIGNORS TO DICTOGRAPH PRODUCTS CORPORATION, A CORPORATION OF VIRGINIA.

'rrnmrnolmazA RECEIvER.

Application lcd November 14, 19237.' Seria1\No. 674,601.

IThis `invention relates to telephone receivers, particularly of the type commonly'f employed, in radio telephoneL and telegraph receiving sets and popularly known as loud speakers. The invention is in the nature of improvements upon the receivers disclosed in the co-pending applications of Henry Koch, Serial No. 628,709 filed March 30, 1923, and No. 661,596liled September 8, 1923, and has for an object to improve and simplify the mechanism' for varying the in fluence of the electromagnetic device upon the diaphragm, and tol provide an improved receiver which is exceptionally simple, durable, l5 relatively inexpensive,- and which will enable a very line relative adjustment of the air gap between the diaphragm and pole pieces of the electromagnetic device. Other objects and advantages will be apparent from the following description of an embodiment of the invention, and the novel features will be pointed out hereinafter in claims.

In the accompanying drawing; Fig. 1 is a sectionalelevation through a receiver constructed in accordance with the invention; and,l

Fig. 2 is a bottom plan of the same. In the illustrated embodiment of the invention, acup shaped base 1, inthe nature of a shell, serves as the base of the receiver forI supporting the operating parts thereof. The shell 1 is supported in an inverted position, as illustrated in Figure 1, upon any suitable surface, and is provided upon its upper face with a tubular projection 2, com- -cally through the 'upper wall of the base..

municating with'the interior of the base shell land serving as a support for the small end of va suitable amplifier horn 3. The inner face of the shell is provided with an an V nular wall 4, substantially concentric with the passage of the tubular extension 2, and a suitable diaphragm 5 `isitted against this annular wall. A cup shaped4 frame 6 is provided along its open edge with a lateral annular flange 7 fitting against the peri heral portion of the diaphragm. Suitable astening means, such as screws 8, pass through the flange 7 and diaphragm into the annular wall 4 forsecuring the cup shaped frame 6 to the base shell 1, and for clamping the periphery of the diaphragm against the an-l nular wall. f f

' A cup shaped memberv 9 .is mounted in the frame 6 forsliding 'movement toward .and from the diaphragm, and suitably supports electromagnets 10 having pole pieces 10n projectlng from the, ends thereof` toward the diaphragm, so thatk when `the member 9 moves toward or from the diaphragm, the pole pieces 10V-will move toward or from the diaphragm. The pole pieces form polar extensions of a permanent magnet within the y member 9, as will be understood in the art.

A stud 11 extends from the member 9 through the frame 6, and is provided with an axial slot 12 Vfor receiving the intermediate portion of a lever 13. A pivot member. 14 passes through the stud and lever for providing an articulated connectionI between them. One end 1-5 of the lever bears upon and fulcrums uponthe frame 6, so that when the other end 16 ofthe lever is moved in one direction, the lever, by reason of this fulcrum. on the frame 6, will pull the member 9 carrying the electromagnetic ,device away from the diaphra A leaf spring 17 is interposed betwee the member 9 and `frame 6, so as to yiel'dingly urge lthe member 9 in agdirection toward the diaphragm, the spring being compressed when the lever 13 is operf ated to pull the/member 9 away :from the diaphragm. A pin 18, carried by the member 9, passes loosely through an aperture the framel 6 so as to slide freely therein as the member 9 moves toward and from the diaphragm, and to prevent rotation of the member 9 within the frame 6. The circuit wires 20 serve to conduct a variable electric current tothe electromagnets 10. ,l An operating member 21 extends vertifor rotation with the member. The engage# ment of the dial 24 with the upper face of the upper wall of the base shell 1 servesfto' limit downward movement of the member 21 without preventing` rotation of the latter. A

Z-shaped bracket 25 is secured by screws '26, 105

or other suitable means, to the upper wall of the base shell, and anf endL angular portion 27 thereof is provided withl an aperture 27a; in which the lower' end of the member 21 is rotatably mounted. I l 1 rlhei'lower end of the member 21 is provided with an axially extended, threaded recess 28, and an element 29 is received within the recess, in threaded engagement with said member. The periphery of the element 29 is provided with ay plurality of spaced notches 31, and a 'pawl or detent 32, in the nature of a. leaf spring, is secured to the bracket in a'position to snap into any of t-he notches 31 which may be brought into alignment therewith. The pawl or detent serves to hold the element 29 against rotation with the member 21, andtherefore when the latter'is rotated, the element 29 will be moved axially of the member 21. The detent or pawl 32 is disposed parallel with the member 21, so as to remain within a notch 31 during the axial movement of the element 29 without releasing the latter. The element 29 abuts against the ,end 16 of the lever 13, so that when the button 23 is roktated in one direction the element 29 will be moved downwardly to rock the lever about its fulcrum and shift the member 9 against the action yof thespring 17. "A pin 33 depends from the lower face of the dial 24 so as to rotate therewith, and a stop pin '34 is provided upon -the upper face of the base shell 1 within the path of the pin 33, the pins -33 and 34 serving to limit the rotation of f the button 23 to approximately one revolu` tion.

.In the operation of the Ireceiver, the circuit wires' 20 are connected to any source of variable electric currents such as a telephone or radio telephone or telegraph circuit. The variable currents will pass through the electro-magnets .10,v and vary the magnetic flux passing through the diaphragm between .the pole pieces 11 of the permanent magnet in accordance with'the variations of the current. These variations of iux will cause corresponding Avibrations of the diaphragm. The vibrating ,diaphragm sets lup. sound waves which pass through the tubular extension 2 'intol the` amplifier horn 3, where the waves are ampliied and discharged. By rotating the button' 23 in one direction the element 29'wil1 be moved axially thereof and rock the lever 13 about its fulcrum upon its `frame 6. The lever in rocking upon its fulcrum will draw ythe electromagnetic device away from the diaphragm against the action of the spring 17 This serves to lessen the infiuence of the electromagnetic device upon. the diaphragm by increasing the air gap between the diaphragm and the pole pleces of the electromagnets.

By rotatingv the button 23 in the other direction the element 29 will be moved in a reverse'direction and away from the end of i the lever 16, whereupon the spring 17 will `operate the electromagnetic device toward the diaphragm so as to reduce the air gap bef tween the pole pieces and the diaphragm.

This movement of the electromagnetic del vice carries the lever toward the element 29 j be observed that by rotating the button 23 the air gap between the pole pieces of the electromagnetic device and the 4diaphragm may be varied.

ln order to initially adjust the air gap, the button 23 is rotated until the pin 33 of the dial engages with the pin 34 on the base shell. The spring detent 32 is flexed out of engagement with the element 29, and the latter is then rotated to cause it to move along the member 2l until the electromagnetic device exerts its maximum magnetic influence upon the diaphragm Without the diaphragm, during its vibrations, hitting the pole pieces 11. The detent 32 is then released and allowed to snap into one of the notches 21 of the element 29 so as to hold the latter in this adjusted position. lThe rotation of the button 23 then serves to carry the electromagextent determined by one rotation of theop- .erating button. The operating button being accessible from the upper face of the base may be readily and conveniently manipulated to vary the air gap and t-hus control the sounds which are emitted by the receiver. 'It will be obvious that various changes in the details and arrangements of parts, herein described and illustrated for the purpose of explaining the naturefof the invention, may be madeby those skilled in the art Within the principle and scope of the invention as expressed in the appended claims.

Claims: 1. ln a telephone receiver, a frame, a diaphragm carried by said frame, an electromagnetic unit mounted in said frame for movement toward and from the diaphragm andA adapted to actuate the said diaphragm magnetically, a stud carried by the unit, a lever articulately connected at an intermediate point to said stud and having a fulcrum at one end on said frame and actuating means adapted to act on the other end of the lever to rock. the lever and thereby adjust the unit relatively lto the diaphragm.

2. In a telephone receiver, a frame, a diaphragm carried by said frame, an electromagnetic unit mounted in said frame for movement toward and from the diaphragm and adapted to actuate the said diaphragm magnetically, a stud carried by the unit, a spring device constantly urging the unit in one direction relatively to .the diaphragm, and a lever articulately connected at an intermediate point to said studland having a fulcrum at one end on the frame enabling operation of the unit in an opposite` direction relatively to the diaphragm, and 5actuating means adapted to act on the other end of the lever to effect such operation.

` cal slow-motion device operatively associated with the other end of said lever for operating the lever against the action of the spring device.

4. In a telephone receiver, a frame, a diaphragm carried by said frame, an electromagnetic unit mounted in said frame for movement toward and from the diaphragm and adapted to actuate the said diaphragm` magnetically, a stud carried by the unit, a p

spring device constantly urging the unit in one direction relatively to thdiaphragm, a lever articulately connected at an intermediate point to said stud vand having a ul- `crum at one end on the. frame enabling operation of the unit in an opposite direction relatlvely to the diaphragm, and a screw :device operatively associated with the other end of said lever for operating the lever against the action of the spring device.

5. In a telephone receiver, a frame, a diaphragm carriedby said frame, an electro,

magnetic unit mountedl in said frame for movement toward and from the diaphragm and adapted to actuate the said diaphragm magnetically, Ya stud carried by the unit, a spring device constantly, urging the unit inv 'one direction relatively to the diaphragm,

a lever articulately connected to said stud and having'a fulcrum on the frame enabling operation of the unit in an opposite direction relatively to the diaphragm, an yoperating member rotatably carried by the frame, an

element threaded to said member, means for holding 'the element against rotation with the member, said element engaging with and operating said lever against` saidl spring `device, whereby rotation of the member will cause an operation of said lever and v4througlh it an adjustment of the unit relatively to t e diaphragm. l i

6.` .In a telephone receiver, a frame, a diaphragm carried vby said frame, an electromagnetic unit mounted in said frame for sprln n `one 4a lever. articulately connected to said stud movement toward and from the diaphragm and adapted to actuate the said diaphragm magnetically, a stud carried by the unit, a

device constantly urging the unit in irection relatively to the diaphragm,

and having a ulcrum on the frame enabling :operation of the unit in an opposite direcing member rotatably carried by the for holding the element against rotation .-w1th the member, said element engaging with and operating said lever against said spring device, whereby rotation of the member w1ll cause an operation of said lever and through it an adjustment of the unit relatively to the diaphragm, said holding'means for said element permitting threaded adjustment of the latter upon said member without rotation of the member whereby the setting of thev unit relatively to the diaphragm for any selected angular position of said member may be varied. v

7. In a telephone receiver, a base, a diaphragm carried by the base in a position to set up sound Waves when vibrated, an electromagnetic unit`mounted in the base for Amovement toward and from the diaphragm and adapted to `magnetically actuate the diahragm, an operating member rotatably car- -fried by the base and yhaving a portion accessible from the outside of the base for 'manual operation, an element having a threaded connection with said operating member, means -or holding the element against rotationv with the member, and a lever fulcrumed at one end on said base and Mconnected at an intermediate point to said unit to move it relatively to the diaphragm, said lever being operated at zthe other end by said element.

8. In 'a telephone receiver, a base, a diaphragm carried by the base in a position to set up soundI waves when vibrated, an

electromagnetic unit mounted in the base for c movement toward and from the .diaphragm and adapted to magnetically actuate the diaphragm, an operating member rotatably carried b the base and having a portion accessible m the outside of the base for manuall operation, an element having a threaded connection with said operating member, means forholding the element against rotation with the member, a lever fulcrumed at one end on said base and coninected at an intermediate point to said unit to move it relatively to the diaphragm, said lever being operated at the other end by said element in one direction, and a spring device for operating said unit in a direction to maintain the lever against the -said element. l

9. In a telephone receiver, a frame, a diaphragm carried by the frame, an electromagnetic diaphra actuating unit carried by the frame ans operable to vary its inluence upon the diaphra an operating member rotatably carried said frame and held against movement axially, an element said element against rotation with the operating member whereby the element will move axially of the member when the latter` is rotated, and means cont-rolled by Said element for operating said unit to vary its influence upon the diaphragm.

l0. ln a telephone receiver, a pair of relatively movable parts, a diaphragm carried by onc ot' the parts, an electromagnetic diaphragni actuating device carried bythe other of said parts whereby when relative movement between the parts occurs the de vary the influence of the device upon the diaphragm.

11. rllhe receiver substantially as set fort-h in claim l() in which the holding means for said element permits initial adjustment of the element relatively to said member.

12. In a telephone receiver, a diaphragm, an electromagnetic device supported in position to actuate said diaphragm, an operating member mounted for rotation and held against movement axially and having a portion adapted to be actuated manually, an element having a threaded connection with said member, means for holding said ele ment against rotation with said member, a lever magnetically independent of the electromagnetic device but articulately connected therewith and operated by said element for varying the inuence of said device upon said diaphragm. f

In witness whereof, we hereunto subscribe our signatures.

HENRY KOCH. FRIEDRICH H. N. WOHLERS. 

